This invention relates to the preparation of partially fried, frozen potato strips which have extended holding quality after finish frying. More particularly, the invention relates to the preparation of frozen, par fried potato strips which exhibit a crisp but tender exterior surface for extended periods of time after finish frying
Control of the textural properties of french fries after finish frying is of great concern to operators of fast food restaurants. Typically, french fries served by fast food restaurants are prepared by finish frying frozen partially fried (i.e., parfried) potato strips in fat or oil. Desirably such parfried and frozen potato strips, after finish frying, exhibit a crisp and tender exterior surface and a fluffy, mealy inner core. However, parfried potato strips presently available suffer from the disadvantage that when finish fried for consumption, they lose their desired crispness within a relatively short period of time and tend to become limp and soggy. This change in texture is due to the migration of internal moisture within the fried strips into the outer surface of the potato strips. Such migration of moisture is accelerated by holding the potato strips, after finish frying, under a heat lamp, a practice commonly used by fast food operators to maintain the french fries at desired serving temperature.
A number of procedures have been proposed heretofore for extending the holding time of french fries, so that the french fries remain crisp and tender for extended periods of time after finish frying, even when held under a heat lamp. For example, U.S. Pat. No. 3,597,227 discloses coating the surface of potato strips with an aqueous dispersion of a high amylose starch prior to deep frying to improve the crispness of finish fried potato strips. U.S. Pat. No. 5,141,759 discloses that potato strips having increased crispness and extended holding time after finish frying are produced by coating the strips, prior to parfrying, with an aqueous starch slurry containing chemically modified ungelatinized potato starch, chemically modified ungelatinized corn starch and rice flour. U.S. Pat. No. 5,302,410 discloses providing blanched potato strips with a "glaze" coating of an aqueous solution having a pH 5.5-8.5 and containing hydrolyzed starch having a DE of less than 12, to provide parfries which retain crispness for an extended period after finish frying. U.S. Pat. No. 5,431,944 discloses the production of french fries having a crispy texture by coating blanched potato strips with a batter mix containing a leavening agent, a blend of starch and high amylose starch, dextrin and a food gum. U.S. Pat. No. 5,622,741 discloses that potato strips having an extended hold time after finish frying are produced by coating blanched potato strips with an aqueous slurry containing corn flour, corn starch and low solubility dextrin.
Some of these prior art procedures have been more effective than others in providing potato strips which retain desired textural characteristics for an extended period after finish frying. However, all of these prior procedures suffer from disadvantages which limit their acceptability to fast food restaurant operators. For example, batter coatings used heretofore, even those designated as thin-coat batters, have a relatively high solids content and deposit a relatively thick batter coating on the surface of the potato strips. Although the batter coated strips have a crisp texture after finish frying, they develop an undesirable degree of toughness and chewiness during holding. Moreover, the batter coating detracts from the natural potato flavor of the product and forms a discernible coating layer on the surface of the french fries to detract from the natural appearance of the finish fried potato strips. The use of batter coatings having a low solids content has not been feasible since such low solids content batters have reduced adherence to the surface of the potato strips and tend to dissociate from the potato strips during parfrying and/or finish frying. While the "glaze" coating on potato strips disclosed in the '410 patent is effective in extending crispness of french fries after finish frying without the development of toughness and chewiness, such "glaze" coatings are not as crisp as batter coated french fries.